Germination studies on pure yeast ascospores

Abstract

Pure ascospore suspensions of three strains of Saccharotnyces cereuisiae have been prepared by sequential treatment with 2-mercaptoethanol, Glusulase, and sonication. Light microscopy and acid-fast staining revealed the presence of only ascospores. Various germination media tested using the ascospore preparation revealed different nutritional requirements for the germination of auxotrophic and prototrophic yeast strains. Acid-fast staining of the germinating ascospores was shown to be an effective method for studying the kinetics of ascospore germination. The anaerobic nature of ascospore germination was demonstrated using this staining technique. SAVARESE, J. J. 1974. Germination studies on pure yeast ascospores. Can. J. Microbiol. 20:1517-1522. Nous avons prepart des suspensions pures d'ascospores de trois lignees de Saccharotnyces cereuisiae par traitement sequentiels avec le 2-mercaptoethanol, le glusulase et la sonication. La microscopie photonique et la coloration "acid fast" revelent la presence d'ascospores seulenlent. Des milieux varies pour la germination en utilisant la preparation des ascospores revelent des exigences nutritionnelles pour la germination des lignees auxotrophique et prototrophique. La coloration "acid fast" des ascospores en germination est une mCthode efficace pour etudier les cinetiques de la germination des ascospores. La nature anaerobique des ascospores en germination fut demontree en i~tilisant cette technique de coloration.[Traduit par le journal]

Involvement of actin and polarisome in morphological change during spore germination of Saccharomyces cerevisiae

“…Early studies revealed extracellular conditions and intracellular activities required for spore germination. A fermentable carbon source, such as glucose and fructose, effectively promotes germination, whereas oxygen is not necessary for spore germination (Palleroni, 1961; Seigel and Miller 1971; Rousseau et al , 1972; Rosseau and Halvorson, 1973; Savarese, 1974; Tingle et al , 1974; Hartig et al , 1981; Donnini et al , 1986; Xu et al , 1992). It was revealed that protein synthesis is required for germination (Rosseau and Halvorson, 1973; Choih et al , 1977), and that the small GTPase Ras2p functions during the earliest event, whereas the cyclin‐dependent protein kinase (CDK) Cdc28p is not required for the whole process of germination (Herman and Rine, 1997).…”

Yeast spore germination: a requirement for Ras protein activity during re-entry into the cell cycle

“…No systematic genetic analysis of germination has ever been performed and hence the genes and precise environmental cues that control this process remain unknown. Early studies of spore germination indicate that this process is controlled by nutrient availability and identify a series of morphological changes that occur to the spore prior to the onset of the first cell cycle (Hashimoto et al ., 1958; Nagashima, 1959; Palleroni, 1961; Rousseau and Halvorson, 1973; Savarese, 1974; Kreger‐Van Rij, 1978; Sando et al ., 1980). In these pioneering studies, germination assays based largely on morphological criteria were used to examine the requirements for spore germination.…”

The Heterotrimeric G-Protein GanB(α)-SfaD(β)-GpgA(γ) Is a Carbon Source Sensor Involved in Early cAMP-Dependent Germination inAspergillus nidulans

“…The primary requirement for initiation of germination and completion of the subsequent steps is the sensing of external signals. Early studies demonstrated that germination of ascospores in Saccharomyces cerevisiae is most efficient in the presence of a readily fermentable carbon source, suggesting that initiation of germination is regulated by nutrient availability (Savarese 1974;Tingleet al 1974). In this regard, glucose has been shown to be necessary and sufficient to induce activation of ascospore germination (Herman and Rine 1997).…”